Precision machine vision inspection systems (or “vision systems” for short) can be utilized to obtain precise dimensional measurements of inspected objects and to inspect various other object characteristics. Such systems may include a computer, a camera and optical system, and a precision stage that is movable in multiple directions so as to allow the camera to scan the features of a workpiece that is being inspected. One exemplary prior art system that is commercially available is the QUICK VISION® series of PC-based vision systems and QVPAK® software available from Mitutoyo America Corporation (MAC), located in Aurora, Ill. The features and operation of the QUICK VISION® series of vision systems and the QVPAK® software are generally described, for example, in the QVPAK 3D CNC Vision Measuring Machine User's Guide, published January 2003, and the QVPAK 3D CNC Vision Measuring Machine Operation Guide, published September 1996, each of which is hereby incorporated by reference in their entirety. This product, as exemplified by the QV-302 Pro model, for example, is able to use a microscope-type optical system to provide images of a workpiece at various magnifications, and move the stage as necessary to traverse the workpiece surface beyond the limits of any single video image. A single video image typically encompasses only a portion of the workpiece being observed or inspected, given the desired magnification, measurement resolution, and physical size limitations of such systems.
Machine vision inspection systems generally utilize automated video inspection. U.S. Pat. No. 6,542,180 teaches various aspects of such automated video inspection and is incorporated herein by reference in its entirety. As taught in the '180 patent, automated video inspection metrology instruments generally have a programming capability that allows an automatic inspection event sequence to be defined by the user for each particular workpiece configuration. This can be implemented by text-based programming, for example, or through a recording mode which progressively “learns” the inspection event sequence by storing a sequence of machine control instructions corresponding to a sequence of inspection operations performed by a user with the aid of a graphical user interface, or through a combination of both methods. Such a recording mode is often referred to as “learn mode” or “training mode.” Once the inspection event sequence is defined in “learn mode,” such a sequence can then be used to automatically acquire (and additionally analyze or inspect) images of a workpiece during “run mode.”
Video tools (or “tools” for short) and other graphical user interface features may be used manually to accomplish manual inspection and/or machine control operations (in “manual mode”). Their set-up parameters and operation can also be recorded during learn mode, in order to create automatic inspection programs, or “part programs.” Video tools may include, for example, edge/boundary detection tools, autofocus tools, shape or pattern matching tools, dimension measuring tools, and the like. Other graphical user interface features may include dialog boxes related to data analysis, step and repeat loop programming, and the like. For example, such tools are routinely used in a variety of commercially available machine vision inspection systems, such as the QUICK VISION® series of vision systems and the associated QVPAK® software, discussed above.
The machine control instructions including the specific inspection event sequence (i.e., how to acquire each image and how to analyze/inspect each acquired image) are generally stored as a “part program” or “workpiece program” that is specific to the particular workpiece configuration. For example, a part program defines how to acquire each image, such as how to position the camera relative to the workpiece, at what lighting level, at what magnification level, etc. Further, the part program defines how to analyze/inspect an acquired image, for example, by using one or more video tools such as edge/boundary detection video tools. The ability to create part programs with instructions that perform a predetermined sequence of inspection operations provides several benefits, including enhanced inspection repeatability, as well as the ability to automatically execute the same part program repeatedly on one or more compatible machine vision inspection systems.
For general-purpose machine vision inspection systems that are intended to be rapidly programmable for a wide variety of workpieces, as exemplified by the previously referenced QUICK VISION® series of PC-based vision systems, it has been conventional for image acquisition operations to be interspersed with image analysis operations and/or feature inspection operations that are performed on the most recently acquired image (referred to herein as “interspersed” type operations). However, there is an increasing demand for general-purpose machine vision inspection systems to provide higher throughput. According to one method, this may be accomplished by performing image acquisition while using continuous relative motion between the camera and the workpiece stage (as opposed to intermittently stopping and starting the relative motion, as required for interspersed type operations), thereby significantly increasing inspection throughput. Such operations are referred to herein as continuous-motion type operations. It is advantageous for such systems to include strobe lighting illumination to assist with the acquisition of images during continuous motion without smearing (or blurring) the image.
High-speed “in-line” vision inspection systems used in high-speed production lines have provided continuous-motion type image acquisition. However, such in-line vision systems typically are dedicated to a single production line and acquire the “same” image over and over again, for successive workpieces on a conveyor system, for example. In such cases, for each image, the motion speed and strobe illumination parameters, etc., are the same. Furthermore, workpiece configurations and/or image acquisition parameters, etc., are rarely changed. Thus, programming methods for such systems have not facilitated rapid programming for an unlimited variety of workpieces, camera positions, image acquisition parameters, etc., by relatively unskilled users.
In contrast, experience has shown that it is essential for general-purpose machine vision inspection systems to facilitate rapid programming for an unlimited variety of workpieces, camera positions, image acquisition parameters, etc., by relatively unskilled users. Previous programming methods for general-purpose machine vision inspection systems have not made the programming of continuous-motion type operations sufficiently easy or fast. Furthermore, previous programming methods have not made the programming of continuous-motion type operations in combination with interspersed-type operations sufficiently easy or fast. Programming systems and methods that can overcome these problems and shortcomings, either separately or in combination, would be desirable.
One exemplary prior art method that overcomes some of these problems and shortcomings is illustrated in U.S. Pat. No. 7,590,276, which is hereby incorporated by reference in its entirety. As described in the '276 patent, a method of part programming is provided which permits a user to readily define multiple image acquisition operations interspersed with associated image analysis operations during learn mode operations, in a natural and intuitively understandable relationship. Then, in the resulting part program, image acquisition operations for at least some of the images are automatically rearranged into a continuous motion image acquisition sequence that acquires images and stores images in a “non-interspersed” manner in order to increase the throughput of the machine vision inspection system.
However, one drawback of certain previous programming methods, such as that illustrated in the '276 patent, is that the continuous stream of image acquisition operations has typically been achieved by analyzing various operations entered by the user during learn mode, and altering or “regrouping” their order in the part program instructions using “regrouped” programming representations and syntax, such that the image acquisition instructions are grouped together for acquiring a plurality of images using continuous motion, and their corresponding image analysis instructions are altered or “regrouped” to follow the image acquisition instructions, such that the image analysis operations need not be interspersed with, or interrupt, the high-speed image acquisition during the continuous motion. As a result, when the part program instructions are recalled for editing or viewing, the image analysis instructions are separated from the acquisition instructions for their corresponding image. This has proven to be confusing for the users of such systems, in that related image acquisition and analysis instructions are separated by intervening “unrelated” image acquisition and image processing instructions, which is non-intuitive and leads to inefficiencies and errors when a user attempts to read or edit the “rearranged” part program instructions. In other words, the rearranged programming representations and syntax for grouping the image acquisition operations together in the part program have made programming and editing of such part programs more difficult for users. A need exists for a part programming syntax, and editing operations and features which overcome these and other deficiencies to allow more efficient, intuitive, and flexible programming and editing of continuous image acquisition part programs for precision machine vision inspection systems.